Continuous dispersion apparatus having multi-step dispersion chambers

ABSTRACT

An apparatus having a cylindrical structure which has therein a rotary shaft extending along the axis of the cylindrical structure to project beyond the lengthwise end portions thereof, and a plurality of dispersion chambers and an arbitrary number of rectifying chambers arranged along the rotary shaft can be used for continuous dispersing in the manufacture of several products. Each of the dispersion chambers and rectifying chambers consists of a space defined by the circumferential surface of the rotary shaft and between adjacent distance collars. Each of the distance collars is fixed at its outer circumferential surface to the inner surface of the cylindrical structure, and forms at a part of its inner circumferential surface in cooperation with the circumferential surface of the rotary shaft an annular slit which constitutes a passage for a material current. The dispersion chamber houses in the inner space thereof a rotary blade having a shearing edge, and fixed to the rotary shaft so that the rotary blade extends at right angles to the longitudinal direction of the rotary shaft. The rectifying chamber houses in the inner space thereof a bearing for the rotary shaft, which is fixed to the inner surface of the cylindrical structure and provided with a plurality of small gaps which constitute passages for the material current.

TECHNICAL FIELD

The present invention relates to a continuous dispersion apparatusutilizable for the manufacture of products in dispersed or emulsifiedstate, for example, in the fields of cosmetics, foods, paints, fuels andcar waxes. More particularly, the present invention relates to acontinuous dispersion apparatus capable of dispersibly mixing hardlymiscible aqueous and oily phases to produce an oil-in-water type orwater-in-oil type state or of efficiently producing a dispersed state ofa solid phase such as a powdery substance in an aqueous and/or oilyphase.

DESCRIPTION OF THE BACKGROUND ART

A manufacturing apparatus for the production of cosmetics such as creamand emulsion, emulsified foods, paints and the like dispersions is knownhaving (1) a vacuum emulsifier, (2) an open emulsifier and (3) acontinuously stirring and kneading reaction heat exchanger (theso-called mixing reactor or scraped surface heat exchangers).

The emulsifier effectuates stirring and emulsification under vacuum in aconfined state. The emulsification is carried out under vacuum so thatthe emulsifier is suitable for the manufacture of sterilized productsand aerial bubble-free products.

The open emulsifier has been used for some time. In this openemulsifier, aerial bubbles tend to enter on emulsification andevaporation of water and the like occurs during stirring foremulsification at a high temperature. In general, evaporation of anamount of about 2-5% based on the amount charged occurs, although itvaries according to the recipe and the amount for batch. Further,careful attention should be paid to the heating temperature, heatingtime, stirring speed and the like. A cream manufactured by the openemulsifier contains about 2-10% by weight of aerial bubbles as comparedwith a cream manufactured by a vacuum emulsifier. In case the resultantcream is charged into a bottle or the like container, therefore, theamount to be charged will be decreased by the amount corresponding tothe aerial bubbles.

The following points are mentioned as problems existing commonly in theabove described vacuum and open emulsifiers:

○1 On account of a batchwise system, an emulsifying tank will inevitablybecome larger so that it takes much time to charge the tank withmaterials and to discharge the emulsion from the tank,thus making thesystem inefficient.

○2 As the emulsifying tank is larger, little turbulence occurs and deadspaces also tend to be formed. Accordingly, cutting of particles withblades of a propeller hardly tends to be effected completely and evenlyso that an entire emulsion will hardly be formed even after the lapse ofa sufficient time.

○3 As the emulsifying tank is larger, it is difficult to obtain thenumber of revolutions necessary for cutting particles (desirably atleast 6,000 r.p.m.). However, only about 3,000 r.p.m. is obtained with adrive having power as high as 7 horse power or more for a tank with acapacity of 300 liters and a drive as high as 15 horse power or more fora tank with a capacity of 1,000 liters, thus making the operationuneconomical.

○4 As the apparatus is large, a number of employees are required for theoperations. Moreover, a lot of cost is required if the apparatus isadditionally installed.

○5 On account of a batchwise system, much time is necessary for theproduction of an emulsion and a warmth-maintaining device is required insome cases, thus making the operation uneconomical.

A substantial structure is required for the continuously stirring andkneading reaction heat exchanger as discussed above wherein startingmaterials dissolved in a starting materials-dissolving tank areemulsified in a preliminary emulsifying tank and the preliminarilyemulsified starting materials are supplied in a constant amount by ametering pump to a mixing reactor. This arrangement is fundamentally acylinder with a jacket and the interior of the cylinder (whereemulsification by stirring is effected) provided with protuberant bladesor scraping blades rotatable at a speed of about 100-600 r.p.m. Ingeneral, the emulsification by stirring is effectuated in the cylinderwith a jacket and then the product is rapidly cooled in a coolingcylinder and is continuously discharged. Further, there is also known asystem wherein starting materials are fed, without using any preliminaryemulsifying tank, from the starting materials-dissolving tank directlyto the body of the mixing reactor for emulsification by the aid of ametering pump and then the product rapidly is cooled in a coolingcylinder and is continuously discharged therefrom. The former is calledthe non-proportional system and the latter the proportional system.

It is characteristic of this apparatus that quick cooling of the productis possible and that the product can continuously be discharged.However, this apparatus has drawbacks is that cleaning of the interiorof the cylinder where blades of a complicate shape are positionedbecomes incomplete and that the product is rapidly cooled so thatcontrol becomes difficult in a recipe system which requires gradualcooling. In any of the non-proportional and proportional systems, thequality of the product may not be definite between the product obtainedin the initial stage of the production and that in the latter stage ofthe production.

A continuously mixing and emulsifying apparatus having a plurality ofmixing chambers is also known. Such an apparatus is disclosed in U.S.Pat. No. 3,807,703 and DOS No. 2,339,530. A mixing and emulsifyingapparatus of this type relates to an apparatus developed chiefly forefficiently producing polyurethane and the like. The mechanism of themixing and emulsification is characterized in that the mixing andemulsification are effected in an axial flow state caused by a voltexeffect according to the Stokes principle by the action of a rotor shapedto have a specific element based on turbine blades or propeller bladesinstalled in the housing and that the starting material flow in a steadyflow state existing in the neighborhood of the outer layer in thehousing is changed to a non-steady flow state by the action of a bafflebar thereby enhancing the mixing efficiency.

In case of manufacturing an emulsion having a very small particle sizeor a highly viscous emulsion (for example, a cream) or dispersion (forexample, a pigment paste) of a high inner phase (the state wherein thecontent of a dispersion phase is greater than that of a matrix phase),however, this mixing and emulsifying apparatus has serious drawbacks aswill be described hereinafter.

1. As the rotor is a one-end-supported type, its rotation becomeseccentric so that a limitation exists preventing at a high speed.Accordingly, the apparatus can be applied for an ordinary emulsion (forexample, a particle size within the range of 1-100μ, optimally 1-5μ) butcan hardly be applied to the manufacture of an emulsion of very fineparticles which requires a high speed of rotation as an indispensablecondition.

2. Since the action of this mixing and emulsifying apparatus is based onmixing and emulsification by a vortex effect, it is difficult to divideparticles into those of less than a certain definite size even if a highspeed of rotation is possible.

3. Even if the shape of the element is changed so as to impart ashearing force, a baffle bar installed in the housing constitutes anobstacle so that a fluid boundary layer portion in the neighborhood ofthe outer layer in the housing forms a dead space, thus giving only anunhomogeneous and unstable emulsion. Especially, in case of the fluidstarting materials having a high viscosity like an emulsion of a highinner phase type, any baffle action by a baffle bar (conversion of asteady flow into a non-steady flow) cannot be expected so that thistendency becomes more significant.

4. Emulsification proceeds in such a manner that the fluid startingmaterials are repeatedly passed through an orifice formed between a landand a bore always in turbulent state. Thus, the emulsion tends to becomeunhomogeneous, having a wide range of particle diameters. On agitationat a high speed, the fluid starting materials per se are heated. In thismixing emulsifier, however, the heat conversion rate is so poor that theemulsion tends to be denatured thermally.

Furthermore, the apparatus itself had the following problems:

1. As the rotor is of an integrated type, the rotor requiresconstruction by a split die type and, as a result of the construction,liquid contents tend to leak out.

2. As the rotor is of a one-end-supported type, a limitation exists inthe number of dispersion chambers to be installed.

3. As the mixing is fundamentally based on a vortex action, the internalpressure in the housing becomes unstable, thus making control of theflow rate difficult.

Thus, an apparatus which satisfies the following conditions is nowgreatly demanded in view of such prior problems:

1. An apparatus operable continuously for emulsification and dispersionand applicable to starting components an materials having a wide rangeof viscosities.

2. A continuous treatment is possible from charging starting materialsto discharging products without the necessity of effecting anypreliminary dispersion.

3. A loss of shearing energy on carrying out dispersion is so littlethat a significant saving of energy is possible as compared with theknown conventional apparatus.

4. Energy conversion toward a fluid is made so stable that productshaving desired particle diameters may be obtained steadily.

5. Thermally unstable starting materials can also be processed withoutany problem.

SUMMARY OF THE INVENTION

The present invention provides the following continuous dispersionapparatus: having multi-step dispersion chambers which comprises a bodyof a cylindrical structure having a sealing assembly on both endsthereof provided with a plurality of inlets for starting materials andan outlet for a dispersion product, a rotary shaft extending i thecylindrical structure in a lengthwise direction along the central axisof the cylindrical structure beyond both ends thereof, and a pluralityof dispersion chambers arranged along the rotary shaft so as to dispersea starting material current from the inlet in the dispersed chambers andto discharge a dispersed product from the outlet, characterized in thata starting material-supplying chamber, a plurality of the dispersionchambers and an arbitrary number of the rectifying chambers are involvedin the cylindrical structure in such a manner that the startingmaterial-supplying chamber consists, at one end of the cylindricalstructure, of a space defined by combining the circumference of thecylindrical structure passages for the starting materials from theplurality of the inlets and the dispersion chambers and the rectifyingchambers are arranged on the circumference of the rotary shaft from oneend to the other end thereof along the axis, each of the dispersionchambers and the rectifying chambers consisting of a space defined bythe circumferential surface of the rotary shaft, one distance collar andan adjacent distance collar thereof. The distance collar is fixed at theouter circumferential surface to the inner wall of the cylindricalstructure. At a part of the inner circumferential surface thereoftogether with the circumferential surface of the rotary shaft, anannular slit is formed which constitutes a passage for the startingmaterial current supplied from the starting material-supplying chamber.The dispersion chamber in the internal space thereof having a rotaryblade with shearing edges which is fixed to the rotary shaft and extendstherefrom at a right angle to the lengthwise direction of the rotaryshaft. The rectifying chamber in the internal space thereof is providedwith a bearing for the rotary shaft, which is fixed to the inner wall ofthe cylindrical structure and provided with a plurality of small gapswhich constitute passageways for the starting material current. Further,the present invention also provides for the above described continuousdispersion apparatus having multi-step dispersion chambers wherein thecylindrical structure is provided on the exterior circumference thereofwith a means for flowing a medium for heating or cooling and optionallyon the outside of the means with a means for allowing an insulatingmaterial t exist.

The term "dispersion" used herein is usually used in a broader sense inphysics and involves such embodiments as a heterogeneous mixing of aliquid phase with another liquid phase immiscible therewith (emulsion)and a fine mixing of a liquid phase with a solid phase insolublethereinto (dispersion or suspension).

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a schematic longitudinal cross-sectional view of an embodimentof the continuous dispersion apparatus the present invention providedwith a means for flowing a medium for heating or cooling and with ameans for allowing an insulating material to exist, a part of which isomitted for easy and better understanding;

FIG. 2 is a schematic longitudinal cross-sectional view of thedispersion chamber;

FIG. 3 is a perspective view of an example of the rotary blade havingshearing edges;

FIG. 4 is a front view of an example of the above described rotaryblade;

FIG. 5-a is an enlarged schematic longitudinal cross-sectional view ofthe dispersion chamber, showing the relation between the dispersionchamber and the rotary blade;

FIG. 5-b is a transverse cross-sectional view of the dispersion chamberin FIG. 5-a cut along the line A--A';

FIG. 6 is a drawing for explaining the effect of the rotary blade havingshearing edges shown in FIG. 4;

FIG. 7 is a drawing for explaining the effect of the tip of the shearingedges;

FIG. 8 is a perspective view showing another example of the rotary bladehaving shearing edges;

FIG. 9 is a partial transverse cross-sectional view showing therelationship between the rotary blade shown in FIG. 8 and a sleeve;

FIG. 10 is a front view showing still another example of the rotaryblade having shearing edges;

FIG. 11 is a schematic longitudinal cross-sectional view showing therelation between the rotary blade and the dispersion chamber in case ofusing the rotary blade shown in FIG. 10;

FIG. 12 is a schematic longitudinal cross-sectional view showing therectifying chamber;

FIGS. 13 and 14 are transverse cross-sectional views showing twoexamples of the rectifying bearing;

FIG. 15 is a drawing for explaining the function of the rectifyingbearing shown in FIG. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The continuous dispersion apparatus of the present invention will now beexplained hereinafter in detail, referring to the drawings.

FIG. 1 is a schematic longitudinal cross-sectional view showing apreferable example of the continuous dispersion apparatus of the presentinvention having multi-step dispersion chambers wherein the apparatus isused in an upright position. A fundamental part of the apparatus of thisinvention comprises a cylindrical structure. The cylindrical structurehas on one end thereof a plurality of inlets 1a and 1b for starting(introducing) materials and a rotary shaft 4 positioned in the center ofthe longitudinal axis of the cylindrical structure and supported by asealing bearing. The bearings 3 also function as a sealing assembly atboth of the terminal ends of the cylindrical structure. A cover 5 isused as need and is used together with a mantle 6 for regulation of thetemperature of this continuous dispersion apparatus. The mantle 6 ispositioned on the outside of a wall 7 of the cylindrical structure, andan insulating material 8 is packed between the cover 5 and the mantle 6.A medium 9 for heating or cooling is introduced between the mantle 6 andthe wall 7 of the cylindrical structure. In the interior of thecylindrical structure, there exist a plurality of distance collars 10.Fundamentally, each of these distance collars 10 is in the form of ahollow cylindrical block and the diameter of the hollow part is at leastlarger than the diameter of the rotary shaft. The outer circumference ofthe rotary shaft 4 may be covered with a hollow sleeve 11. A hollow zoneor space is formed between adjacent distance collars 10 to define adispersion chamber 14. In case a bearing 19 for the rotary shaft ispositioned between the distance collar 10 and an adjacent distancecollar 10, two spaces are also formed between the two distance collars10 vicinal to both sides of the bearing, thus defining a rectifyingchamber 15. This rectifying chamber changes the turbulent flow of thefluid to a laminar flow as will be discussed hereinbelow. Between thedistance collar 10 and the rotary shaft 4 or the sleeve 11, an annularslit is formed, through which, as a passageway 16, starting materialcurrents introduced from inlets 1a and 1b and combined in a startingmaterial-supplying chamber 17 formed on the circumference of the rotaryshaft is passed. The rotary shaft 4 or the sleeve 11 is equipped with arotary blade 18 having shearing edges which extends at the right angleto the longitudinal axis of the rotary shaft. The rotary blade 18 isentered in the dispersion chamber 14. A rectifying bearing 19 providedso as to separate the rectifying chamber 15 into two portions is fixedaround a cylindrical outer portion (outer circumference) thereof to thewall 7 of the body and is contacted at an inner portion (innercircumference) thereof partially with the rotary shaft 4 or the sleeve11 thereof. The use of the sleeve 11 is convenient for mounting therotary blade 18 to the shaft 4 and is used for protection thereof. Thisis due to the reason that as the rotary shaft 4 is rotated at a highspeed and thus tends to undergo abrasion, the use of the sleeve protectsthe shaft 4 from abrasion and the life of the whole apparatus can beextended requiring only the sleeve to be exchanged after a period ofuse. Thus, the present invention is economically desirable.

In FIG. 2 showing the dispersion chamber 14 is shown in detail. Thestarting material current a is introduced into the dispersion chamberthrough a passageway 16, i.e. an annular slit formed between the innercircumferential wall of the distance collar 10 and the sleeve 11. Theinner tip of the distance collar 10 forms an orifice mouthpiece 20extending in the direction in which the starting material current amoves and toward the center axis. The starting material a flows in aturbulent state in the dispersion chamber 14 and through an orificebetween the orifice mouthpiece 20 and the sleeve 11. Together with therotary shaft 4, the rotary blade 18 with shearing edges is rotated at ahigh speed. The rotary blade 18 is fixed to the rotary shaft 4 throughthe sleeve 11 so as to be at a right angle to the axial direction of therotary shaft. The starting material current a flowing in a turbulentstate in the dispersion chamber 14 undergoes a strong shearing action bythe rotary blade 18 having shearing edges so that the mixing anddispersion of the current is highly promoted. The starting materialcurrent a thus treated is again allowed to pass through a passageway 16in the form of a slit between the sleeve 11 and the distance collar 10and sent to a second dispersion chamber where the current undergoes asimilar treatment. The starting material current is further sent to thesubsequent dispersion chambers for repeated mixing and dispersion andthen to the rectifying chamber 15.

In FIGS. 3 and 4, the blade portion 18a of the rotary blade 18 hasportions of a side-cutter type as shearing .edges, which are bentalternately in opposite directions. This edge portion has a point F witha sharp angled portion and a point G as an obtuse angled portion. Thisrotary blade 18 is rotatable in either direction of A or B. In general,the rotation in the direction of B is ordinary but the rotation in thedirection of A achieves a higher efficiency in the apparatus of thisinvention for the reason as will be described hereinafter.

In FIG. 5-a, each dispersion chamber 14 houses the rotary blade 18having the shearing edges of a side-cutter type which are alternatelybent in opposition directions. The rotary blade 18 is positioned in thedispersion chamber 14 in such a manner that the circumference of therotary blade 18 is entirely surrounded with the distance collar 10forming the dispersion chamber 14. The diameter D of the blade and thatof the dispersion chamber are desirably determined in such a manner thatthe front end edges of the rotary blade 18 may be positioned in aboundary layer portion formed between the starting material current aand the sleeve position 25 (Theory of Prandth referred to). In theapparatus of this invention wherein the orifice mouthpiece 20 isprovided by the distance collar 10, the ejection of the startingmaterial current a under high pressure can prevent the formation of anydead space in the dispersion chamber 14 so that the rotation energy ofthe rotary blade 18 can effectively be converted to shearing energy,emulsifying energy, turning energy, dispersion energy, etc.

In FIG. 5-b, the dispersion effect according to the direction ofrotation of the rotary blade is better in the direction A than direct B.The diameter 18a of the rotary blade portion (D in FIG. 5-a), thethickness of the wall 7 of the body, the thickness of the sleeveposition 25 of the dispersion chamber 14, and the relation in spacebetween the diameter 18a of the rotary blade 18 and the sleeve position25 can visibly be understood from FIGS. 5-a and 5-b. In case of thediameter of the rotary blade 18 being D in one example, the diameter ofthe sleeve position 25 of the dispersion chamber is 1.05-1.1 D and theclearance between the blade 18 and the sleeve position 25 is 0.025-0.05D. Further, the clearance between the blade 18 and the orificemouthpiece 20 of the distance collar 10 is 0.02-0.04 D while the lengthd of the portion at the tip of the blade 18 alternately bent in oppositedirections is 0.2-0.4 D and the length of the sleeve portion 25 isslightly larger than the length d. The clearance between the inner wallof the distance collar 10 and the blade 18 is about 0.005-0.1 D, and thelength of the distance collar 10 except the sleeve position, i.e thelength of the portion forming the annular slit and the orifice is about0.5-1.0 D. These ratios show one example of the standard size of theindividual parts and vary according to the viscosity and flow speed ofthe starting material current, the materials consisting of the apparatusand the shape of the surface, etc.

In FIG. 6 the fact that the rotation of the rotary blade 18 in thedirection A is preferably for efficiency is explained. In the blade 18a,the point F which is a distant from the point G by ΔR in the diametricdirection is considered to be a point of collision. In this case, ahigher energy is created theoretically in the point F by a difference ofΔR×2×π in circumferential rotation speed than in the point G so that theformation of a higher cavitation is found. As shown in FIG. 7, the pointF forms a knife edge of θ(15°-50°) serving to minimize the particle sizeby a greater shearing force produced by the rotation. This rotary blade18a is suited for emulsification, dispersion and mixing of variousstarting material currents having low to high viscosities of 1-200,000cps and effective for the production of cream, emulsion or the likehaving a high viscosity.

In FIGS. 8 and 9 another example 18b of the rotary blade 18 is shown. Inblade 18b, the shearing edge 24 projects at a certain angle from thesurface of the body of the rotary blade and is suitable for dispersionof a solid such as a pigment for which pulverization and crashing arenecessary with a strong shearing blade. In case of dispersing a liquidphase, the rotation of a rotation blade 18b gives a strong surfacepressure by the action of specific edges 24 and greater crashing forceand shearing force are imparted by a synergistic effect of centrifugalforce by rotation and the surface pressure to the current beingpressurized by the surface pressure so that dispersion of the current isstrongly effected. In the distance collar 10 especially shown in FIG. 9,tooth-shaped slits are formed on the sleeve position 25 so that thefluid runs once toward the inside of the sleeve position and thenundergoes the action of the edge 24, thus exerting significant hearingforce.

In FIGS. 10 and 11 still another example 18c of the rotary blade 18 isshown. In this example, the blades 23 having shearing edges of therotary blade 18c are mounted to the periphery of a basal plate 22 to befixed to the rotary shaft 4 in such manner that they face alternately inopposite directions. Especially in FIG. 11, the shape of the dispersionchamber 14 is formed in compliance with the shape of the blades 23 ofthe rotary blade 18c so that no dead space exists in the dispersionchamber 14 and dispersion can be effected efficiently.

In FIG. 12, an annular rectifying bearing 19 is shown in the rectifyingchamber 15, with its outer circumferential part being fixed to the wall7 of the body. In other words, the rectifying chamber 15 is separatedinto two portions by the rectifyinq bearing 19 and the two separatedrectifying chambers 15 are mutually in communication by slits 19a whichfunction as a passageway 19a for a fluid.

FIG. 13 shows the case of the slit 19a each being a small cylindricalslit having a diameter of several millimeters. In this example, thesesmall cylindrical slits are arranged, two in each case, at a definiteinterval in the radial direction. FIG. 14 shows an example wherein theslit 19a are different in shape from and large in space than that shownin FIG. 13 and has a plurality of slits (3 slits) are arranged at agiven interval. In both drawings, a portion of the rectifying bearing incontact with the rotary shaft 4 or the sleeve 11 has a plurality of(three) small eccentric slits 19b and somewhat larger slits 19c.

The starting material current a passed through the dispersion chamber 14retains a residual shearing stress by the action of the rotary blade 18with an axially rotating flow by the rotation of the rotary shaft 4 andis entered in the rectifying chamber 15 and in front of the rectifyingbearing 19. By the rectifying bearing 19, the starting material currenta is separated into two streams, one of which is allowed to pass throughthe cylindrical slits of several millimeters arranged radially orsomewhat larger slits 19a and stabilized or homogenized and the other ofwhich is introduced by the rotation of the rotary shaft 4 into the slit19b in a very small amount and into the slit 19c in the remainingamount. In the slit 19c, the stream achieves a centrifugal force by therotation of the rotary shaft 4 and creates internal stress by the slit19c. The stream further creates a higher internal stress by entering inthe very small slit 19b from the slit 19c so that any swing of the shaft4 by resonance is prevented by the forces in three directions exertingfrom the very small slits 19b toward the shaft 4, showing the effect asauto-centering as indicated in FIG. 15. This results in minimizingfluctuation of the shearing point in the dispersion chamber andcontributes to enhancement of dispersibility.

FIG. 15 visibly shows the function of the rectifying bearing 19 with theauto-centering function.

The apparatus of the present invention can be used in a vertical orhorizontal direction with respect to the central axis of the cylindricalstructure. However, the use in a vertical position, i.e. an uprightposition makes the operation more efficiently by utilization of gravity.A problem of the generation of bubbles, etc. can be solved except in thecase of the initial stage of the process. Further, it is alsoadvantageous that during the rotation of the rotary shaft 4, itseccentricity is minimized by the gyrostatic action according to theprinciple of tops. The material for the apparatus can properly beselected from metals, glass-lined materials, ceramics, synthetic resins,etc. The size of the apparatus is properly determined according to theintended purpose, the amounts of starting materials, etc.

The size and number of the dispersion chambers and the size and numberof the rectifying chambers as well as the order and arrangement of thesecan adequately be determined according to the desired use. A preferableembodiment for the arrangement of the dispersion chambers and therectifying chambers is shown in Table 1.

According to the properties of substances and materials to be used asstarting materials, the properties of products, etc., a medium forheating or cooling such as hot water or cold water can be introducedinto a space between the mantle 6 and the cylindrical structure 7. Incase the difference in temperature between the ambient temperature andthe temperature of the medium is significant, a cover 5 as atemperature-maintaining means may optionally be employed and a spacebetween the cover 5 and the mantle 6 may be charged with aheat-insulating material such as asbestos, glass wool, kapok and thelike to enhance the efficiency for maintaining the temperature.

The dispersion operation of the apparatus of the present invention iscarried out follows:

(1) Starting material currents are introduced from the inlets 1a and 1bfor starting materials and are mixed in the mixing chamber 17 and amixed stream flows in the axial direction through passageway 16 formedbetween the rotary shaft 4 or the sleeve 11 and the distance collar 10into the dispersion chamber 14 via the orifice mouthpiece 20.

(2) In the dispersion chamber 14, a laminar flow is rapidly converted toa turbulent flow especially by the rotation of the rotary blade 18 andthe confined dispersion chamber surrounding the blade whereby adispersion effect is efficiently exerted.

(3) The starting material current repeatedly dispersed in the dispersionchambers is thermally stabilized in the passageway 16 and introducedinto the rectifying chamber 15. The current is converted to a laminarflow by the slits 19a and 19c provided in the axial direction in therectifying bearing 19 in the rectifying chamber 15 and again introducedinto the passageway 16 between the distance collar 10 and the shaft 4 orthe sleeve 11.

(4) By thus repeating the laminar flow action and the turbulent flowaction by providing a plurality of dispersion chambers and an arbitrarynumber of rectifying chambers, the starting material current ishomogeneously and entirely dispersed and the dispersed product isdischarged from an outlet 2 for the product.

The apparatus of the present invention has the following advantages:

(1) A homogeneous dispersion is attained within a short period of timeby repeating the process wherein materials to be treated are passedthrough very small slits while being stabilized terminally and rapidlydiffused in the dispersion chambers and by passing the current throughthe rectifying chamber where the current is made stable.

(2) In a batchwise dispersion apparatus, a dead space is usually formed.In the apparatus of the present invention, however, no dead space isformed and loss of energy is small by providing each dispersion chamberwith an orifice mouthpiece at the entrance thereof and arranging thefront end of the rotary blade so as to shear the boundary layer of thecurrent.

(3) The blade of the rotary blade has a shape not in possession of anypropelling power so that control of the amount of the flowing currentcan easily be carried out. As the blade has a shape capable of obtaininga high cavitation state to such a degree that bubbles are not generated,an extremely good dispersion effect is exerted by impact in the limiteddispersion chambers in a high cavitation state and by the shearing forceof the rotary blade.

(4) In the past, severe selection, administration and control arenecessary for properties of starting materials and operation conditionsincluding especially the mixing method in order to control the particlesize distribution in a very narrow range or to obtain a dispersionwherein the particle size is as small as about 0.011-0.5μAccording tothe apparatus of the present is obtained without the necessity of suchstrict selection, administration and control.

(5) Conversion of high energy is easily made so that the amount of asurfactant conventionally required may be reduced to about 1/2.

(6) The apparatus can be constructed in a significantly compact size,e.g. about 1/10 as small as a batchwise emulsifier.

(7) Products are obtained continuously without the necessity of anyoperation for a preliminary dispersion. Further, a worker-freeautomation process is possible for the operation and control thereof.

Table 2 is a table for comparison of features of the apparatus of thepresent invention with generally reported emulsifiers. As are evidentfrom the comparative table, the merits of the apparatus of thisinvention are summarized as follows:

1. A continuous treatment is possible without of necessity of anypreliminary mixing.

2. Although the apparatus is for a continuous treatment, it isapplicable to a viscosity over a wide range with respect to theviscosity of materials to be treated.

3. A shearing energy is compulsorily given to the starting materialcurrent in a narrow space dispersion chamber so that loss of energy isminimized and the energy can significantly be saved as compared with theprior art apparatus.

4. As the energy for dispersion is stable, no fluctuation occurs inparticle diameter add the desired particle size is always obtained in asteady manner.

5. As the apparatus is provided with a means for controllingtemperature, no problem will arise in the dispersing operation forthermally unstable materials.

Given below are Experimental Examples wherein the continuous dispersingapparatus of the present invention having a multi-step dispersionchambers are used. It is to be construed that utilization of the presentinvention is not limited to these examples.

Experimental Example 1

A high inner phase (high oil content) oil-in-water type emulsion:

To an aqueous phase prepared by heating 16 parts of water and anadequate amount of a sugar at 80°-85° C. a surfactant phase comprised of6 parts of 1,3-butylene glycol and 6 parts of polyoxyethylene hardenedcastor oil (100E·O) was added. After dissolving (or homogenizing) thesurfactant phase, an oily phase prepared by adding adequate amounts of apreservative and antioxidant to 15 parts of olive oil, 37 parts ofliquid paraffin, 7 parts of vaseline and 5 parts of beeswax and heatingthe mixture at 50°-60° C. was added to the homogenized phase underagiation. The resultant mixture is then passed continuously through theapparatus of this invention (Dispersion Conditions: the number ofdispersion chambers 6, the capacity of dispersion chambers about 15 cm³,the speed for transporting the mixture 0.4 l/min, the shape of blades18a and the number of rotation of the blades 8,000 r.p.m.) and cooledwhereby a stable oil-in-water type emulsion was obtained which had aparticle diameter of 0.1-1.0μ.

Experimental Example 2

A high inner phase oil-in-water type emulsion:

To an oily phase prepared by adding adequate amounts of a preservativeand an antioxidant to an oily substance comprising 15 parts of oliveoil, 37 parts of liquid paraffin, 7 parts of vaselin, 5 parts of beeswaxand 6 parts of polyoxyethylene hardened center (100 E O) and heating themixture at 50°-60° C. was added under agitation an aqueous phaseprepared by adding an adequate amount of a sugar to 16 parts of waterand 4 parts of 1,3-butylene glycol and heating the mixture at 50°-60° C.The resultant mixture was then passed continuously through the apparatusof this invention (Dispersion Conditions: the number of dispersionchambers 6, the capacity of dispersion chambers about 15 cm³, the speedfor transporting the mixture 0.4 l/min., the shape of blades 18a and thenumber of rotation of blades 8,000 r.p.m.) and cooled whereby a stableoil-in-water type emulsion was obtained which had a particle diameter of0.1-1.0μ.

Experimental Example 3

An oil-in-water type emulsion:

To an oily phase prepared by warming at 75°-85° C. an oily componentcomprising 8 parts of a fatty acid, 3 parts of cetanol and 11 parts ofsqualane, as surfactant component comprising 1 part ofpolyethyleneglycol monostearate (150 E·O), 3 parts of sorbitanmonostearate and 1 part of polyoxyethylenesorbitan monostearate (20E.O), and adequate amounts of a preservative and an antioxidant wasadded with stirring an aqueous phase prepared by warming at 75°-85° C.60 parts of water, 8 parts of 1,3-butylene glycol and 9 parts ofpropylene glycol. The resultant mixture was then passed continuouslythrough the apparatus of this invention (Dispersion Conditions: thenumber of dispersion chambers 6, the capacity of dispersion chambersabout 15 cm³, the speed for transporting the mixture 0.6 l/min., theshape of blades 18a and the number of revolution of blades 6,000 r.p.m.)and cooled whereby a stable emulsion was obtained which had a particlediameter of 1.0-3.0μ.

Experimental Example 4

An oil-in-water emulsion:

To an oily phase prepared by warming at 70°-80° C. 10 parts of liquidparaffin, 9 parts of microcrystalline wax and 16 parts of a silicone oiland 1 part of glycerol monostearate was added with stirring an aqueousphase prepared by warming at 70°-80° C. 55 parts of water, 3 parts ofethyl alcohol, 5 parts of 1,3-butylene glycol and an adequate amount ofa preservative. After the addition, 2 parts of a gelling agent (LAPONITEXLG, Veegum HV) was dispersed further in the mixture. The resultantmixture was then passed through the apparatus of this invention(Dispersion Conditions: the number of dispersion chambers 6, thecapacity of dispersion chambers about 15 cm³, the speed for transportingthe mixture 0.6 l/min., the shape of blades 18a and the number ofrotation of blades 6,000 r.p.m.) and cooled whereby an oil-in-water typedispersion was obtained which had a particle diameter of 1.0-3.0μ.

Experimental Example 5

A water-in-oil type emulsion:

To an oily phase prepared by warming at 80°-85° C. a mixture of an oilycomponent comprising 2 parts of solid paraffin, 3 parts of beeswax and13 parts of liquid paraffin, a surfactant component comprising 3 partsof diglyceryl monoleate, and an adequate amount of a preservative and anantioxidant was added with stirring an aqueous phase prepared by adding7 parts of a 54% aqueous solution of Maltitol to 67 parts of water and 5parts of 1,3-butylene glycol and warming the mixture at 80°-85° C. Theresultant emulsion was then dispersed under the same conditions asdescribed in Experimental Example 1 whereby a stable water-in-oil typeemulsion was obtained which had a particle diameter of 2.0-3.0μ.

Experimental Example 6

A pigment dispersion in an oily medium:

An adequate amount of an antioxidant was added to a mixture of 50-75parts of castor oil, 7-10 parts of cetyl 2-ethylhexanoate, 3-5 parts ofasilicone oil and 0.9-1.5 parts of polyoxyethylene polyoxypropylenecetyl ether. Further, 10-30 parts of a combination of a tar pigment anda white pigment each capable of being used for cosmetics waspreliminarily dispersed in the mixture. The resultant mixture wascontinuously passed through the apparatus of this invention (DispersionConditions: the dispersion chambers 11, the capacity of the dispersionchambers about 15 cm³, the speed for transporting the mixture 0.5l/min., the shape of blades 18b, sleeve position 25 and the number ofrotation of blades 8,000 r.p.m.) while being cooled whereby anyexothermic phenomenon could be prevented and pigment dispersion with aparticle diameter of 5-20μ was obtained.

Experimental Example 7

A pigment dispersion in an oily medium:

In 45 parts of squalane and 1 part of sorbitan sesquioleate waspreliminary dispersed 5-25 parts of an inorganic pigment. The resultantmixture was continuously passed through the apparatus of the presentinvention (Dispersion Conditions: dispersion chambers 11, the capacityof the dispersion chamber about 15 cm³, the speed for transporting themixture 0.5 l/min., the shape of blades 18b sleeve position 25 and thenumber of rotation of blades 8,000 r.p.m.) while being cooled wherebyany exothermic phenomenon could be prevented and a pigment dispersionwith a particle diameter of 5-20μ was obtained.

Experimental Example 8

A pigment dispersion in an aqueous medium:

In 50 parts of water and 30 parts of polyethylene glycol (200) waspreliminarily dispersed 5-25 parts of an inorganic pigment. Theresultant mixture was continuously passed through the apparatus of thepresent invention (Dispersion Conditions: the dispersion chambers 11,the capacity of the dispersion chambers about 15 cm³, the speed oftransporting the mixture 0.5 l/min., the shape of blades 18b, sleeveposition 25 and the number of rotation of blades 8,000 r.p.m.) whilebeing cooled whereby any exothermic phenomenon could be prevented and apigment dispersion with a particle diameter of 5-20μ was obtained.

                                      TABLE 1                                     __________________________________________________________________________                Number                                                                             Number                 Vol-    Num-                                      of Dis-                                                                            of Rec-                                                                            Num-              ume     ber of                                    persion                                                                            tifying                                                                            ber of                                                                            Arrangement Pattern                                                                         of  Shape                                                                             Revo-                                                                             Particle                              Cham-                                                                              Cham-                                                                              Cham-                                                                              ○  Dispersion Chamber                                                               Flow                                                                              of  lution                                                                            Diameter                              bers bers bers                                                                               Rectifying Chamber                                                                         l/min                                                                             Blade                                                                             HM  μ Remarks              __________________________________________________________________________    Oil-in-water type                                                                          6   2     8  ○○ ○○ ○.circl                              e.              1-10                                                                            18a 6000                                                                              4.5-5.5                   Emulsion A                                                                    Water-in-oil type                                                                          6   2     8  ○○ ○○ ○.circl                              e.              1-10                                                                            18a 6000                                                                              4.5-5.5                   Emulsion A                                                                    Oil-in-water type                                                                          6   1     7  ○○○ ○○.circle                              .             0.4-4                                                                             18a 6000                                                                              1.0-3.0                   Emulsion B                                                                    Water-in-oil type                                                                          6   1     7  ○○○ ○○.circle                              .             0.4-4                                                                             18a 6000                                                                              1.0-3.0                   Emulsion B                                                                    High inner phase                                                                          12   1    13  ○○○○○○                               ○○○○○.circle                              .             0.4-4                                                                             18a 8000                                                                              0.1-1.0                   oil-in-water type                                                             Emulsion                                                                      High inner phase                                                                          12   1    13  ○○○○○○                               ○○○○○.circle                              .             0.4-4                                                                             18a 8000                                                                              0.1-1.0                   water-in-oil type                                                             Emulsion                                                                      Micro-emulsion                                                                            12   2    14  ○○○○ ○.circle                              .○○ ○○○.circl                              e.            0.3-3                                                                             18a 12000                                                                             0.05-0.1                  Pigment dispersion                                                                        12   1    13  ○○○○○○                               ○○○○○.circle                              .              0.5-10                                                                           18c 8000                                                                               5-20                                                                              Sleeve               (Oil phase dispersion                                    position of          Water phase dispersion)                                  10, con-                                                                      cavoconvex                                                                    shape                __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Comparison in Performance of Various Emulsifying Apparatus                                                Circumferential                                               High-Shearing   Speed of Rotor of                                             Dispersion      Colloid mill                                      Physical    apparatus       (ft/min)                    Apparatus of          properties  (5,000 ft/min)                                                                         Roll mill                                                                            5,000   10,000                                                                              Ball mill                                                                           Homogenizer                                                                           this                  __________________________________________________________________________                                                            invention             Range of viscosity (cp)                                                                   5,000-2 × 10                                                                     10.sup.3 -10.sup.5                                                                   1,000-3 × 10.sup.4                                                              1-5,000                                                                             300-6,000                                                                           1-2,000 1-200,000             Optimum viscosity (cp)                                                                    5 × 10.sup.4                                                                     --     15,000  2,000 500-2,400                                                                           1-200   5,000-10,000          Range of particle                                                                         1-100    0.5-50 2-100   1-100 0.5-100                                                                             0.5-20  0.01-100              diameter (μ)                                                               Optimum particle                                                                          2        0.5-1  2-4     1-3   1     0.1-2   0.1-2                 diameter (μ)                                                               Range       1-5,000  6-28 lb/h                                                                            8-150 gpm                                                                             8-160 gpm                                                                           1 qt- 15-     4-1,000 l/hr          of          gal      (Per in. of          2,000 gph                                                                           14,000 gph                    capacity             Roll length)                                             Range of    1-200    1-60   2-200   2-200 --    2-200   1-60                  horse power                                                                   Discrimination of                                                                         Batchwise                                                                              Batchwise                                                                            Continuous                                                                            Continu-                                                                            Batchwise                                                                           Continuous                                                                            Continuous            "Continuous" or                     ous   and                                 "batchwise"                               Continuous                          Adequateness to                                                                           No       No     Yes     Yes   Yes   Yes     No                    low boiling point                                                             solvents                                                                      Adequateness to                                                                           No       No     Up to   Up to 15 psi                                                                              Up to   1.5 psi               a pressurized               100 psi 100 psi                                                                             Normal                                                                              10,000 psi                                                                            Normal                system                                    pressure      pressure              Adequateness to                                                                           Yes      No     Yes     Yes   Yes   Yes     Yes                   an aqueous phase                                                              Pulverization                                                                             No       No     No      No    Yes   No      No                    capacity                                                                      Necessity of                                                                              No       Yes    Yes     Yes   No    Yes     No                    Preliminary                                                                   Mixing                                                                        __________________________________________________________________________     (Excerpted from General Data on New Surfactants, The publishing departmen     of KeieiKaihatsu Center, published on January 1 of Sho. 55)              

The continuous dispersion apparatus of the present invention canefficiently produce a well homogeneously dispersed product without thenecessity of any preliminary dispersion of the starting materials andtherefore can be utilized widely for the manufacture of cosmetics, forexample, creams and emulsions for cosmetic use. The present inventioncan also be utilized for the manufacture of various foods such as ediblecreams, dressings and soaps, paints containing very fine pigments in ahomogeneously dispersed state, and liquid fuels containing very finesolid, for example, coal in a dispersed state. Further, the presentinvention can be used in the manufacture of car waxes and the likeindustrial materials, solid phase-liquid phase dispersions and liquidphase-liquid phase dispersions.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

We claim:
 1. A continuous dispersion apparatus comprising:a cylindricalstructure having two ends with a sealing assembly on both ends thereofprovided with at least one inlet for introducing materials and an outletfor a dispersion product; a rotary shaft extending in the cylindricalstructure in a lengthwise direction along a central axis thereof, saidrotary shaft extending beyond both ends of said cylindrical structureand having a circumferential surface; a plurality of dispersion chamberseach having an inlet and outlet, said chambers being positioned withinsaid cylindrical structure and being arranged along the rotary shaft fordispersing a starting material current from the inlet in the dispersedchambers and for discharging a dispersed product the outlet thereof; astarting material-supplying chamber positioned within the cylindricalstructure at one end thereof and having a space defined by at least thecircumference of the cylindrical structure, said chamber permittingpassage of the materials introduced from the at least one inlet; aplurality of aligned distance collars extending along the cylindricalbody, said dispersion chambers being arranged on the circumference ofthe rotary shaft from one end to the other end thereof and along thecentral axis, each of the dispersion chambers consisting of a spacedefined by the circumferential surface of the rotary shaft and adjacentdistance collars, the distance collars being fixed to an inner wall ofthe cylindrical structure and forming together with the circumferentialsurface of the rotary shaft an annular slit which constitutes a passagefor the starting material current supplied from the startingmaterial-supplying chamber; a rotary blade provided in each of thedispersion chambers and having shearing edges, said rotary blade beingfixed to the rotary shaft and extending therefrom generally at a rightangle to the lengthwise direction of the rotary shaft; and at least onerectifying chamber provided along the cylindrical structure between atleast two of the dispersion chambers, said rectifying chamber having aplurality of small gaps which constitute passageways for the startingmaterial current, whereby said starting material current travels throughsaid at least one inlet, said starting material-supplying chamber, atleast one dispersion chamber wherein said current has turbulent flow andthen through said rectifying chamber wherein said current has a laminarflow and then through another dispersion chamber wherein said currentagain has a turbulent flow and then through said outlet in order toproduce the dispersed product.
 2. The continuous dispersion apparatusaccording to claim 1, wherein the cylindrical structure is in an uprightposition.
 3. The continuous dispersion apparatus according to claim 2,wherein an inside part of the distance collar further extends toward thecircumference of the rotary shaft to form an orifice mouthpiece.
 4. Thecontinuous dispersion apparatus according to claim I, wherein an insidepart of the distance collar further extends toward the circumference ofthe rotary shaft to form an orifice mouthpiece.
 5. The continuousdispersion apparatus according to claim 1, wherein the cylindricalstructure is in an upright position.
 6. The continuous dispersionapparatus according to claim 1, wherein an inside part of the distancecollar further extends toward the circumference of the rotary shaft toform an orifice mouthpiece.
 7. The continuous dispersion apparatus asrecited in claim 1, further comprising means for circulating a mediumfor one of heating and cooling of the material current, said means forcirculating being provided on the circumferential surface of saidcylindrical structure.
 8. The continuous dispersion apparatus as recitedin claim 7, further comprising means for insulating said means forcirculating.